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本文概述了采用烷基金属盐水解法制备超细陶瓷粉和用铸膜法制备陶瓷薄膜的新工艺,着重介绍了氧化铝超细粉及其基片的制造方法,对比了新法制品与普通同类制品的机械、热及电气性能。 相似文献
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介绍了纳米陶瓷颗粒增强金属基复合材料的常用制备技术。对固相烧结法和液态铸造法等工艺方法的机理、特点和现阶段开发程度,以及由这些制备工艺所开发的新材料的优异的微观组织和力学性能进行了全面分析,综合评价了各种工艺的优缺点。由于降低了基体金属对陶瓷颗粒的润湿性要求,高能球磨法成为国内外制备该种材料的主要方法之一。与高能球磨法相比,超声辅助液相铸造技术由于能使纳米颗粒在金属熔体中有良好的润湿性并均匀分布,且可以近净成型、制造成本低,因此也备受瞩目。最后,指出了现有制备方法中存在的问题及其进一步的发展趋势。 相似文献
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摘要:本文在陶瓷衬底上面利用磁控溅射的方法镀上一层厚金属钛,用不同方法对金属钛层进行表面处理,处理后的衬底放在微波等离子体化学气相沉积腔中,在相同的沉积条件下制备出不同微米金刚石薄膜。对不同的薄膜的微观表面形态、结构组成进行对比研究;对不同的薄膜用二极管型结构测试了它们的场致发射电子的性能,并对发射机理进行了深入的研究。最终分析出不同方法处理的衬底,对微米金刚石聚晶薄膜生长及场发射特性的影响的原因。 相似文献
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NbN具有较高的临界电流密度 ,较高的临界超导转变温度和良好的力学性能 ,在微电子 ,传感器 ,微机械 ,超导电子学和表面强化领域等方面有广阔的应用前景[1] 。NbN薄膜具有高硬度 ,高耐磨性 ,耐腐蚀性[2 ] 和良好的热稳定性[3 ] ,使其成为一种重要的表面涂层材料。本文研究了氮分压对磁控反应溅射NbN薄膜微结构和力学性能的影响。NbN薄膜在SPC 35 0多靶磁控溅射仪上制备 ,采用射频阴极 ,纯Nb(99 9% )靶作为Nb材料来源 ,溅射室背底真空为 5× 10 -4Pa ,采用Ar N2 混合气体进行反应沉积 ,其中Ar分压为 0 3Pa ,N2 … 相似文献
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本文讨论了激光引发NH_3/SiH_4系统的化学气相合成高纯Si_3N_4超细粉未的实验参数和反应条件。在参考实验条件下,制备出粒径20nm、均匀球形、纯度98%的Si_3N_4粉末。 相似文献
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SnO2/Si的光伏特性 总被引:1,自引:0,他引:1
采用CVD方法在硅单晶上制备SnO2薄膜,对不同硅衬底及在不同温度下淀积SnO2制得SnO2/Si进行光电压谱的测量,得出最佳的制备温度;采用类金属半导体接触模型,推导出有关计算公式,计算得出其介面复合速度和异质结势垒宽度等参数。 相似文献
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采用高纯氧化物,经充分球磨混合后的粉料作为烧结原始粉料。经单轴单向在10MPa压力下预压成型后,将生坯体置于热压烧结炉中进行无压真空(10^-3Pa)烧结,于1650~1800℃保温2~10h,最后得到Nd:YAG透明陶瓷。并利用XRD,SEM对所得样片进行表征,最后用紫外可见分光光度计对样片进行透光率测试。在本实验中,使用适量的二氧化硅作为烧结助剂。 相似文献
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Mechanical alloying of the Fe50Co50 equiatomic-magnetic alloy from elemental powders has been studied. Two milling speeds of 200 rpm and 300 rpm were used to
process these powders. The as-milled powders were characterized using scanning electron microscopy (SEM), energy-dispersive
x-ray spectroscopy (EDX), x-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry
(VSM). The mixing of Fe and Co was completed in 200 min at a milling speed of 300 rpm; however, an increase in saturation
magnetization was observed up to 10-h milling, indicating an increase in compositional homogeneity as a function of milling
time. These findings were also reflected in the XRD results. During the milling of Fe and Co at 300 rpm, an increase of powder
size was observed after 100-min milling. Further milling at 300 rpm led to a reduction in powder size; the decrease of powder
size was more effective when milling was conducted at 200 rpm. This was attributed to a difference in the milling mechanisms
dominating at these two speeds. The TEM observation showed that a banded microstructure was observed in the as-milled powders.
The banded structure consists of grains, many of which show texture effects. After further milling, the banded structure became
finer, then randomly arranged, and finally disappeared. 相似文献
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In this work, iron-doped SnO2 powders were prepared by two methods: mechanical alloying and mechanochemical alloying with successive thermal treatment. The influence of different milling conditions such as ball to powder weight ratio, milling time, rotation velocity of supporting disc and the type of iron starting reactive and their Fe concentration on the structural and magnetic properties of the products were investigated. A greater incorporation of Fe in the SnO2 structure was observed when the samples were prepared by using mechanochemical alloying and successive thermal treatment. 相似文献
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采用电弧熔炼和高能球磨工艺制备了Nd11Fe86Cr3合金微粉,使用SEM、XRD和网络矢量分析仪分析了球磨时间对合金微粉的形貌、相结构及吸波性能的影响。结果表明:所制合金微粉颗粒均呈片状形貌,由Nd2Fe17相和α-Fe相组成;随着球磨时间的增加,Nd2Fe17相强度逐渐减弱,α-Fe相强度逐渐增强,吸波峰频率先向低频移动,后略向高频移动,球磨60 h的样品吸收峰频率最低;球磨时间相同的合金的吸收峰频率随涂层厚度增加向低频移动,反射率最小值降低,吸波带宽变窄。 相似文献
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扁平化对FeSi吸波材料微波电磁性能的影响 总被引:1,自引:3,他引:1
为阐明吸收剂颗粒形状与吸波材料微波电磁性能之间的关系,采用机械球磨工艺对气雾化球形FeSi合金粉末进行扁平化处理并制成FeSi吸波材料。借助SEM和矢量网络分析仪,研究了球磨时间对FeSi颗粒形貌及1~18GHz内吸波材料电磁参数与吸波性能的影响。结果表明:随着球磨时间的增加,FeSi颗粒的扁平率增大。与未球磨样品相比,球磨32h的FeSi合金吸波材料的ε'在整个频率范围内增大了0.5倍,μ'(在1GHz时)由1.24增大到1.94,μ"(在1GHz时)由1.00增大到1.30。扁平化处理明显改善了FeSi吸波材料的低频吸波性。 相似文献
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采用机械研磨工艺制备了片状羰基铁粉,并以此制备了羰基铁粉复合材料。研究了研磨时间对羰基铁粉复合材料电磁性能的影响,并对羰基铁粉吸波涂层进行了优化设计。结果表明:当研磨时间小于12 h时,随着研磨时间的增加,羰基铁粉复合材料的介电常数和磁导率逐渐增大。以研磨12 h的羰基铁粉(厚0.7 mm)为底层,原始羰基铁粉为表层(厚1.4 mm)的双层结构吸波涂层性能最优,其反射损耗在3.12~18.00 GHz频域范围内小于–8 dB,在2~18 GHz频域范围内为–9.8 dB(平均值)。该双层结构涂层可用于微波低频段的宽频薄层吸波涂层的制备。 相似文献
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Yaping Wang Bingjun Ding 《Components and Packaging Technologies, IEEE Transactions on》1999,22(3):467-472
The microcrystalline and nanocrystalline CuCr alloys prepared by high-energy ball milling and hot pressing were investigated in this paper. The experimental results show that the nanocrystalline Cu-Cr alloy powders are obtained by high energy ball milling, and the milled powders appear flaked or equiaxed morphology with or without liquid medium addition. The grain size of near fully dense alloys consolidated at 850 and 1200 K from milled powders is less than 100 nm and about 2-3 μm, respectively. The ability to withstand high voltage of the nanocrystalline CuCr materials in vacuum is much higher than that of microcrystalline materials. The breakdown first takes place on the Cu-rich phase in the microcrystalline CuCr materials. For nanocrystalline CuCr materials, the breakdown exhibits a diffusional feature, in which the arc can move to the whole contact surface in a breakdown 相似文献
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高纯微晶氧化铝陶瓷的研制 总被引:3,自引:0,他引:3
选用超细高纯Al2O3粉为原料.分析了不同方法掺杂MgO添加剂及掺杂不同氧化物添加剂的Al2O3陶瓷显微结构.实验结果表明,利用包覆将MgO均匀加入到Al2O3粉体中,可以制备出致密细晶Al2O3陶瓷;此外,向Al2O3微粉中掺杂ZnO,也可以制备出细晶Al2O3陶瓷.而Y2O3掺杂及ZnO与Y2O3和MgO共掺杂的Al2O3陶瓷中有晶粒异常长大现象. 相似文献